Macromolecular materials are very useful as viscosification agents when dissolved in an appropriate solvent system. The major reason for this viscosity enhancement is due to the very large dimensions of the individual polymer chain. Any increase in the size of the polymer chain will produce a corresponding enhancement in the viscosity of the solution. This effect is maximized when the polymer is dissolved in a "good" solvent. Therefore, in general, a hydrocarbon soluble polymer is useful for thickening hydrocarbon solvents, while a water soluble polymer is appropriate for increasing the viscosity of aqueous systems. With regard to aqueous solutions, water soluble nonionic polymers and high charge density sulfonated or carboxylated polyelectrolytes are quite useful in this regard and are commonly used materials. However, the solution properties of the former family of materials are controlled primarily through modification of the molecular weight of the polymer and through changes in the level of dissolved polymer. These materials become especially effective at concentrations where the individual polymer chains begin to overlap. This "transition" is commonly referred to in the literature as the chain overlap concentration or simply C*. It should be noted that in most nonionic polymers of commercial interest, a relatively large amount of polymer is required in order to reach the required viscosity level.
This approach is undesirable from an economic viewpoint.
In this instant invention is described the finding that a novel family of cationic-alkyl containing monomers intimately mixed with a family of anionic-alkyl containing monomers, i.e. both polymerizable moieties, form large structures in solution. The dimensions of these structures are comparable or larger than polymeric chains. As a result, these structures termed vesicles, formed from these monomers are useful and very effective viscosifiers for aqueous solutions. In addition, these monomer mixtures have markedly unique and improved solution properties, as compared to conventional water soluble polymers. These fluids formed with the monomer mixtures can adequately be described as polymerizable vesicle fluids.
In addition, these unusual and novel interactions opens up a potentially interesting area in the utilization of these specific structures in a number of areas including oil field chemicals, encapsulation procedures, drug delivery, lubrication, shear thickening drilling fluids and the like.
Furthermore, in this instant invention is described the finding that again a novel family of cationic-alkyl containing monomers intimately mixed with a family of anionic-alkyl containing monomers, i.e., both polymerizable moieties, form large structures in solution. The dimensions of these structures are comparable or larger than polymeric chains. An intimate mixture of these structures with a water soluble copolymer containing long alkyl groups produce a novel viscoelastic fluid. It is important to note that the alkyl group, i.e. hydrophobic moiety, is an essential requirement for the effective utilization of this invention. In essence, the long alkyl groups of preferentially interacts, i.e., compatabilized, with the vesicle bilayer structure This interaction allows the alkyl-containing polymer to interact with a number of individual vesicles. As a result, a dynamic three-dimensional structure of vesicles are formed "tied" together via the long polymer chains.
These copolymers are based on, but not limited to, the incorporation of the above alkyl-containing monomers into an acrylamide backbone structure. Furthermore, these vesicles are based on, but not limited to, the mixture of polymerizable cationic and polymerizable anionic monomer units.